Calcium Counts in Runners

Long term marathon runners have greater plaque volume than sedentary controls.

A group in Germany looked at coronary artery calcium counts in several male marathon runners in their 50s who had each done at least five marathons and found increased number counts. This seemed counter intuitive, but most had started running later in life and may have been smokers. I thought it would be interesting to look at men who had committed to the marathon distance for many years and helped pull together a group to study men who had run at least one marathon a year for 25 years or more. Some in the group had run several marathons a year for 25 or more years. The results of the study were recently published in Missouri Medicine (Schwartz RS, et al. Increased Coronary Artery Plaque Volume Among Male Marathon Runners. Missouri Medicine 111(2): 85-90, 2014) along with an opinion piece and an editorial.

The study showed the same number of coronary calcifications (calcium counts) in the runners as in the nearly matched control group, but the calcium plaque volumes were greater and the difference was statistically significant in the runner group. Of note, the running group also had less high blood pressure, less diabetes, less hyperlipidemia, lower body weights and BMI, and higher HDL (good) cholesterols; all good things from a health perspective. There were also more smokers in the running group. What do the results mean for you and your future running plans?

A friend of mine wrote an essay entitled “Statistically significant, but clinically relevant?” The underlying premise was that statistics may show a true difference, but does that difference make the finding clinically useful in decision making and long term risk stratification. The conclusion of the calcium plaque paper is that long term marathon runners have paradoxically greater plaque volume than sedentary controls. The accompanying articles seem to carry that difference into the realm of greater risk ascribed to high volume running over long periods of time. Since many of us run for cardioprotection, the results may cause one to pause and consider how much you run.

We do know from studies of marathon runners that there are some reversible short term changes in heart damage markers following the race, especially in runners who start the race with less training. The question we have not answered is whether those short term changes repeated regularly cause problems for runners later in life. We also know that sedentary people are at more risk for heart attack when active and of developing other chronic medical conditions than regular exercisers. Where the studies are not clear regarding outcomes are in the high volume exercisers compared to more moderate volume runners in terms of length and quality of life.

I think it is important to remember that the percentage of people in the US and worldwide who are regularly active is small and the percentage of runners who run one or more marathons a year for 25 or more years is exceedingly small. If you are in the 3-5 miles 3-5 times a week group of runners, this study does not involve you at all. If you are annual or more marathon runner, it may (stress the “may”) have implications. I would not change my patterns based on this study. There have been no deaths during activity in the study group that I am aware of and certainly none have died during the Medtronic Twin Cities Marathon (source of the study group).

As always, if you have any symptoms of heart disease or you have questions regarding your heart safety, you should meet with your physician.

I hope this helps.

Cheers,

Bill

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